Atlantis Highlights in Material Sciences and Technology (AHMST), volume 1 International Symposium "Engineering and Earth Sciences: Applied and Fundamental Research" (ISEES 2019) Rare Communities of the Desert Steppes of the Russian Caspian Sea Region and Their Preservation Safronova I.N. Laboratory of General Geobotany V.L. Komarov Botanical Institute of the RAS, Saint-Petersburg, Russia [email protected] Abstract – The phytocenotic diversity of the desert steppes is type is represented by the Stipa sareptana + Artemisia preserved due to the presence of the Bogdinsko-Baskunchaksky lerchiana steppes. They are formed on soils of different Nature Reserve and Elton Natural Park in the southern steppe mechanical composition (loamy, loam sandy) and slightly subzone of the Russian Caspian Sea region. Steppes in the Trans- saline. Loam sandy soils are commonly represented by Stipa Volga region are more diverse than those in the Sarpinskaya lessingiana + Artemisia lerchiana steppes (hemipsammophytic lowland. Agropyron desertorum + Artemisia taurica petrophytic variant). Stipa capillata + Artemisia lerchiana steppes are less steppes do not stretch as far as the west of the Volga. Petrophytic common. Sandy soils are covered by plant communities of two series of communities on the slopes of Bolshoye Bogdo Mountain feather grass species – Stipa capillata and S. pennata, with two and halophytic complexes along the shores of Lake Elton include wormwood species – Artemisia lerchiana and A. marschalliana rare communities of species found on western and eastern – as codominates (psammophytic variant). Along with feather distribution limits. These include communities of Artemisia semiarida, since Bolshoye Bogdo Mountain is the farthest western grass steppes, Festuca valesiaca and Agropyron desertorum habitat of this wormwood, far from the main range of the species. halophyte steppes on saline variation of light chestnut soils are The spectrum of communities of dwarf semishrub perennial common. saltworts (Anabasis salsa, Atriplex cana, Camphorosma Wormwood-grass steppes on light chestnut soils form monspeliaca) and wormwoods (Artemisia lerchiana, A. taurica, complexes with dwarf semishrub communities (Artemisia A. semiarida) features the specificity of the desert steppes of the lerchiana, A. pauciflora, Camphorosma monspeliaca, etc.) on Russian Caspian Sea region. solonetz. Keywords – steppes; petrophytic; halophytic; communities of The vegetation cover of the southern subzone as well as the Agropyron desertorum; Artemisia taurica; Artemisia semiarida; entire steppe zone is greatly changed by plowing, pastures, Anabasis salsa. haying, fires, and phytomeliorative works. Large areas are occupied by anthropogenic communities of wormwoods I. INTRODUCTION (Artemisia austriaca, A. lerchiana, and A. taurica) arising Protected areas play a big role in conservation of steppe during overgrazing and on deposits –. vegetation biodiversity. More than 20 years ago (in 1997), the Due to the presence of the Bogdinsko-Baskunchaksky Bogdinsko-Baskunchaksky Nature Reserve, and, a little later in Nature Reserve and Elton Natural Park in the southern steppe 2001, Elton Natural Park were created in the Russian Caspian subzone of the Russian Caspian Sea region, the phytocenotic Sea region. They are located in the southern subzone of the diversity of the desert steppes is preserved. steppe zone, where desert steppes (dwarf semishrub-bunch grasses) are formed. In the Trans-Volga region, the steppes are more diverse than those in the Sarpinskaya lowland. In addition to the plains with The Trans-Volga region, the southern subzone includes the homogeneous and complex cover, in the protected areas there area between 49ᴼ40′ N in the north and 48ᴼ N in the south, and are hills (Bolshoye Bogdo Mountain, 150.4 m above sea level, to the west of the Volga River, there is the largest area of the and Ulagan Mountain, 69 m above sea level ) composed of Sarpinskaya lowland (Karte der natürlichen Vegetation various rocks (limestone, sandstone, saline clay). Their slopes Europas..., 2000 a, b). The relief of the Sarpinskaya lowland is are covered by petrophytic communities. On the shores of salty leveled and features various forms of meso- and microrelief. Baskunchak and Elton lakes hyperhalophytic complexes are The Trans-Volga region is characterized by salt-dome formed. Petrophytic communities and halophytic complexes structures, the largest of which are paragenetic conjugations of include rare communities of species found on the western and Bolshoye Bogdo Mountain (150.4 m above sea level ) and Lake eastern distribution limits. Baskunchak, Ulagan Mountain (69 m above sea level) and Lake Elton located within the southern steppe subzone. Desert steppes on the plains of Bogdino-Baskunchak reserve are characterized by the same properties as in European The desert steppes of the Russian Caspian Sea region are Russia as a whole. The relief of the plains is flat with not numerous in species composition and not diverse in depressions, sometimes cut by ravines, or complicated by many ecological variats (Safronova, Stepanova, 2018). The zonal sinkholes with caves. Light chestnut soils are of different Copyright © 2019, the Authors. Published by Atlantis Press. 634 This is an open access article under the CC BY-NC license (http://creativecommons.org/licenses/by-nc/4.0/). Atlantis Highlights in Material Sciences and Technology (AHMST), volume 1 mechanical composition (loamy, loam sandy and sandy) and In the Trans-Volga region, in the Bogdinsko- different degrees of salinity. The shore of Lake Baskunchak is Baskunchaksky Nature Reserve, on slopes of Bolshoye Bogdo steep with numerous ravines. Zonal Stipa sareptana steppes in Mountain of Triassic limestones with gravelly loamy carbonate the southern subzone of the steppe zone are found and light chestnut soils, peculiar petrophytic steppes of Agropyron preserved throughout the reserve. Communities of Stipa desertorum are formed. Artemisia taurica, which has an sareptana, and Stipa sareptana + Artemisia lerchiana, and eastern distribution limit in the Trans-Volga region, is Stipa sareptana + Anabasis aphylla) occupy very large areas codominant in these steppes. This type of plant communities is along flat slopes of hills and in the plains between sinkholes absent within the southern steppe subzone to the west of the and on the sides of the sinkholes. Stipa lessingiana and Stipa Volga River. capillata steppes are rare. The communities of more than 30 formations play a significant role in the vegetation cover. Artemisia taurica Willd. is wormwood from the subgenus Seriphidium, a primitive dwarf semishrub, Eastern Black Sea, The greatest diversity of formations is represented on the Pre-Caucasian, Western Caspian, foothills and plain steppe Bolshoye Bogdo Mountain, which is a salt dome covered by species, halophyte and halopetrophyte, penetrates in the desert Permian and Triassic, and Quaternary deposits. Bolshoye zone through disturbed lands. It has a disjunctive area. In the Bogdo Mountain has a heterogeneous lithological composition Crimea and in the Prisivashye, A. taurica is participated in (limestone, red saline clay, sandstone), various types of relief halophytic steppes of Agropyron pectiniforme and grows on and a different degree of development of the soil profile. The deposits. On the slopes of the Yergeni upland and in the conditions on its slopes are favorable for formation of rare Sarpinskaya lowland this wormwood and A. lerchiana are communities of species located in the South of European codominants of Stipa sareptana steppes. In some places, it Russia on eastern (Artemisia taurica) and western (Artemisia dominates on deposits. It does not exhibit continuous semiarida, Anabasis salsa, Suaeda physophora) borders of distribution between the Yergeni upland and the Volga River. ranges. The communities with Artemisia taurica and halophytes (Anabasis salsa, Suaeda physophora) form peculiar In the Trans-Volga region, only several habitats of complexes along the shores of Lake Elton. Artemisia taurica are known. It is indicated by F.Ya. Levina for the left bank of the Volga to the north of Volgograd (Levina, 1963). In addition, as already mentioned above, A. taurica is II. RARE COMMUNITIES IN THE BOGDINO-BASKUNCHAK relevant as a codominant and dominant species in the NATURE RESERVE communities of the desert steppes on Triassic limestones of Bolshoye Bogdo Mountain, and less often on the Permian red A. Agropyron desertorum + Artemisia taurica and Artemisia clay. Communities of Artemisia taurica are part of halophytic taurica + Agropyron desertorum steppes complexes on solonchak and solonetz soils on the north-eastern and northern shores of Lake Elton. Agropyron desertorum (Fisch. Ex Link.) Schult. is firm- The slopes of Bolshoye Bogdo Mountain are gravelly, bunch grass that plays an important role in the vegetation cover therefore, communities of Artemisia taurica are rather sparse. of the southern steppe subzone, Mongolian-Kazakh species Their total projective cover is 50–65%. The total number of extending far to the west in the Black Sea region (Lavrenko, species is 55, and one community includes 26–35 species. The 1980). projective cover of Agropyron desertorum is 15−30%. Among In the Sarpinskaya lowland, the subshrub and desert wheat grasses, Poa bulbosa, Stipa lessingiana and Catabrosella grass steppes of Agropyron desertorum with dwarf semishrubs humilis are common in small quantities. The projective cover occupy rather large